EP1339259A1 - Electric heating fabric - Google Patents

Abstract

A woven fibrous article that generates heat upon application ofelectrical power has a woven fibrous body consisting of a set (14) ofnon-conductive warp yarns (20,24) and a set (16) of non-conductivefilling or weft yarns (28). One of the set of non-conductive warp yarnsand the set of non-conductive filling or weft yarns, in one or morefirst regions (18), consists of relatively more coarse yarns (20) and inone or more second regions (22) consists of relatively more fine yarns(24) with electrical conductor elements (26) extending generally alongthe second regions of the woven fibrous body to connect the plurality ofspaced apart electrical conductance heating elements (30) in a parallelelectrical circuit to a source of electrical power. The other of the setof non-conductive warp yarns and the set of non-conductive filling orweft yarns, in the one or more first regions and in the one or moresecond regions, consists of relatively more fine yarns, with a pluralityof spaced apart electrical conductance heating elements (30) in the formof conductive elements joined in the woven fibrous body with the otherof the set of non-conductive warp yarns and the set of non-conductivefilling or weft yarns to extend generally between opposite the secondregions (22) of the woven fibrous body. In one embodiment, fleece may beformed on one or both surfaces of the woven fibrous body by finishingfibers of the relatively more coarse yarns in the one or more firstregions of the set of non-conductive warp yarns or non-conductivefilling or weft yarns, in a manner to avoid damage to electricalconductivity performance of the conductive elements joined with the setof yarns of the woven fibrous body. A method of forming a woven fibrousarticle of the invention is also described.

Description

TECHNICAL FIELD
• This application is: a continuation-in-part of U.S. Application No. 09/791,237, filedFebruary 23, 2001, now pending, which is a continuation-in-part of U.S. Application No.09/697,100, filed October 26, 2000, now pending, which is a continuation-in-part of U.S.Application No. 09/395,326, filed September 13, 1999, now U.S. Patent No. 6,160,246,issued December 12, 2000, which is a division of U.S. Application No. 09/296,375, filedApril 22, 1999, now abandoned; a continuation-in-part of U.S. Application No. 09/592,235,filed June 12, 2000, now pending; and a continuation-in-part of U.S. Application No.09/703,089, filed October 31, 2000, now U.S. Patent No. 6,307,189, issued October 23,2001, which is a division of U.S. Application No. 09/468,627, filed December 21, 1999, nowU.S. Patent No. 6,215,111, issued April 10, 2001; the complete disclosures of all of whichare incorporated herein by reference.
• The invention relates to woven, fibrous fabric articles that generate heat/warmth uponapplication of electricity.
BACKGROUND
• Fabric or fibrous heating/warming articles are known, e.g., in the form of electricblankets, heating and warming pads and mats, heated garments, and the like. Typically, theseheating/warming articles consist of a body defining one or a series of envelopes or tubularpassageways into which electrical conductance heating wires or elements have been inserted.In some instances, the electric conductance heating wires are integrally incorporated into thebody during its formation, e.g. by weaving or knitting. Relatively flexible electricconductance heating wires or elements, e.g., in the form of a core of insulating material, e.g.,yarn, about which is disposed an electrical conductive element, e.g., a helically wrappedmetal wire or an extruded sheath of one or more layers of conductive plastic, have beenfabricated directly into the woven or knitted structure of a fabric body. For example, inKishimoto U.S. 5,422,462, conductive yarns are selectively substituted for warp and/or weftyarns during formation of a woven body. The conductive yarns are then connected at theirends to a source of electrical current.
SUMMARY
• According to one aspect of the invention, a woven fibrous article adapted to generateheat upon application of electrical power comprises a woven fibrous body comprising a set ofnon-conductive warp yarns and a set of non-conductive filling or weft yarns, one of the set ofnon-conductive warp yarns and the set of non-conductive filling or weft yarns in one or morefirst regions comprising relatively more coarse yarns and in one or more second regionscomprising relatively more fine yarns with electrical conductor elements extending generallyalong the second regions of the woven fibrous body, and the other of the set of non-conductivewarp yarns and the set of non-conductive filling or weft yarns in the one or morefirst regions and in the one or more second regions comprising relatively more fine yarns,with a plurality of spaced apart electrical conductance heating elements in the form ofconductive elements joined in the woven fibrous body with the other of the set of non-conductivewarp yarns and the set of non-conductive filling or weft yarns to extend generallybetween opposite second regions of the woven fibrous body, the conductor elements beingadapted to connect the plurality of spaced apart electrical conductance heating elements in aparallel electrical circuit to a source of electrical power.
• Preferred embodiments of this aspect of the invention may include one or more of thefollowing additional features. The woven fibrous article has fleece upon at least one surfaceof the woven fibrous body, formed by finishing fibers of the relatively more coarse yarns inthe one or more first regions of the one of the set of non-conductive warp yarns and the set ofnon-conductive filling or weft yarns in a manner to avoid damage to electrical conductivityperformance of the electrical conductance heating elements joined with the other of the set ofnon-conductive warp yarns and the set of non-conductive filling or weft yarns of the wovenfibrous body. The woven fibrous body has fleece formed in the relatively more coarse non-conductivefibers upon one surface or upon both surfaces. In the one or more first regions,the set of non-conducting warp yarns comprises the relatively more coarse yarns and the setof non-conducting filling or weft yarns comprises the relatively more fine yarns. Preferably,the one or more second regions comprises selvedge or edge regions. Alternatively, in one ormore first regions, the set of non-conducting filling or weft yarns comprises the relativelymore coarse yarns and the set of non-conducting warp yarns comprises the relatively morefine yarns. Preferably, the one or more second regions comprises spaced regions with one or more first regions disposed therebetween. The one or more second regions comprises aplurality of spaced second regions with one or more first regions disposed therebetween. Aseries of at least three electrical conductance heating elements of the plurality of electricalconductance heating elements are symmetrically spaced. Selected of the electricalconductance heating elements are asymmetrically spaced to provide selected localizedregions of heating. Selected of the conductive elements have relatively lower linearresistance than other of the conductive elements, to provide selected localized regions ofrelatively greater heating. Selected of the conductive elements of relatively lower linearresistance are symmetrically spaced and/or asymmetrically spaced. The conductive elementshave the form of a conductive yarn. The fibrous body comprises hydrophilic material and/orhydrophobic material. The electrical conductor elements are adapted for connecting theplurality of spaced-apart electrical conductance heating elements in the parallel electricalcircuit to a power source, e.g., of alternating current or of direct current, e.g. a batterymounted to the woven fibrous body. The electrical conductor elements are woven into thesecond regions of the woven fibrous body, e.g., with the non-conductive warp yarns or withthe non-conductive filling or weft yarns. The electrical conductor elements comprise at leasttwo yarns. The electrical conductor elements, at least in part, are applied as a conductivepaste. The electrical conductor elements comprise a conductive wire. The electricalconductor elements, at least in part, are applied as a conductive hot melt adhesive. Theelectrical conductor elements comprise a conductive yarn or a conductive thread. Theelectrical conductor elements are attached upon a surface in a second region of the wovenfibrous body. The electrical conductor elements are attached: by stitching, e.g. embroiderystitching, by sewing, by adhesive, by laminating, by mechanical fastening, and/or by strainrelief fastening. The electrical conductance heating element has the form of a conductiveyarn comprising a core, an electrical conductance heating filament, a sheath materialwrapped about the core, and/or an overwrap comprising insulating material wrapped aboutthe core and the sheath. In one embodiment, the core may comprises the electricalconductance heating element and the sheath comprises insulating material. In anotherembodiment, the core comprises insulating material and the sheath wrapped about the corecomprises the electrical conductance heating element. The electrical conductance heatingelement may instead have the form of a conductive yarn comprising an electrical conductance heating filament. The electrical conductance heating element has electricalresistivity in the range of about 0.1 ohm/cm to about 500 ohm/cm.
• According to one aspect of the invention, a woven fibrous article adapted to generateheat upon application of electrical power is formed by a method comprising the steps of:joining a set of non-conductive warp yarns and a set of non-conductive filling or weft yarnsto form a woven fibrous body, one of the set of non-conductive warp yarns and the set ofnon-conductive filling or weft yarns in one or more first regions comprising relatively morecoarse yarns and in one or more second regions comprising relatively more fine yarns and theother of the set of non-conductive warp yarns and the set of non-conductive filling or weftyarns in the one or more first regions and in the one or more second regions comprisingrelatively more fine yarns, joining, in the woven fibrous body, with the other of the set ofnon-conductive warp yarns and the set of non-conductive filling or weft yarns, the pluralityof spaced apart electrical conductance heating elements in the form of conductive elements,to extend generally between opposite second regions of the woven fibrous body, andconnecting the plurality of spaced apart electrical conductance heating elements to electricalconductor elements extending generally along the second regions of the woven fibrous bodyto form a parallel electrical circuit for connection to a source of electrical power.
• Preferred embodiments of this aspect of the invention may include the followingadditional feature. The method further comprises the step of: finishing relatively more coarseyarns fibers in the one or more first regions of the set of the non-conductive warp yarns andthe set of non-conductive filling or weft yarns in a manner to avoid damage to electricalconductivity performance of the conductive elements joined with the other of the set of non-conductivewarp yarns and the set of non-conductive filling or weft yarns of the wovenfibrous body.
• According to yet another aspect of the invention, a method of forming a wovenfibrous article adapted to generate heat upon application of electrical power comprises thesteps of: joining a set of non-conductive warp yarns and a set of non-conductive filling orweft yarns to form a woven fibrous body, one of the set of non-conductive warp yarns andthe set of non-conductive filling or weft yarns in one or more first regions comprisingrelatively more coarse yarns and in one or more second regions comprising relatively morefine yarns and the other of the set of non-conductive warp yarns and the set of non-conductive filling or weft yarns in the one or more first regions and in the one or moresecond regions comprising relatively more fine yarns, joining, in the woven fibrous body,with the other of the set of non-conductive warp yarns and the set of non-conductive fillingor weft yarns, the plurality of spaced apart electrical conductance heating elements in theform of conductive elements, to extend generally between opposite second regions of thewoven fibrous body, and connecting the plurality of spaced apart electrical conductanceheating elements to electrical conductor elements extending generally along the secondregions of the woven fibrous body to form a parallel electrical circuit for connection to asource of electrical power.
• Preferred embodiments of this aspect of invention may include one or more of thefollowing additional features. The method further comprises the steps of: finishing relativelymore coarse yarns fibers in the one or more first regions of the set of the non-conductivewarp yarns and the set of non-conductive filling or weft yarns in a manner to avoid damageto electrical conductivity performance of the conductive elements joined with the other of theset of non-conductive warp yarns and the set of non-conductive filling or weft yarns of thewoven fibrous body. The method further comprises the step of connecting the conductiveelement to a source of electric power and generating heat. The method further comprises thestep of connecting the conductive element to a source of electric power comprisingalternating current and generating heat. The method further comprises the step of connectingthe conductive element to a source of electric power comprising direct current, e.g. in theform of a battery, which may be mounted to the woven fibrous article, and generating heat.The method further comprises the step of rendering elements of the woven fibrous bodyhydrophilic or rendering elements of the woven fibrous body hydrophobic.
• Objectives of the invention include to provide woven, fibrous electric heating articles,e.g. electric blankets, heating and warming pads, heated garments, etc., into which a pluralityof spaced-apart electric conductance heating members, in the form of conductive elements,are joined with non-conductive yarns or fibers. The woven fibrous body of the heating articleis subsequently subjected to a finishing process, e.g., relatively more coarse non-conductiveyarns in selected (first) regions at one or both surfaces of the body may be napped, brushed,sanded, etc., in a manner to avoid damage to electrical conductance of the electricconductance heating elements, to form fleece. In a planar structure, such as an electric heating blanket, the electric conductance heating members are connected at their ends, e.g.,in selected (second) regions of relatively more fine yarns along opposite selvedge or edgeregions, or in spaced regions at opposite edges of first regions, of the planar body, i.e., of theblanket, and may be powered by alternating current or direct current, e.g., by one or morebatteries mounted to the body of the woven fibrous heating/warming article.
• The details of one or more embodiments of the invention are set forth in the accompanyingdrawings and the description below. Other features, objects, and advantages of theinvention will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF DRAWINGS
• FIG 1 is a perspective view of a woven fibrous electric heating article of theinvention, e.g., in the form of an electric blanket or an electric mattress pad; and
• FIGS. 2 and 3 are enlarged top plan views of selected regions of the woven fibrouselectric heating article of FIG1, showing electrical conductance heating elements placed withpredetermined symmetrical spacing and asymmetrical spacing, respectively.
• FIGS. 4, 4A and 4B are end section views of different embodiments of woven fibrouselectric heating articles of the invention, without a raised surface (FIG. 4), with fleece formedon one surface (FIG. 4A), and with fleece formed upon both surfaces (FIG. 4B).
• FIG. 5 is a perspective view of another embodiment of a woven fibrous electricheating article of the invention in the form of an electric stadium blanket; and
• FIGS. 6, 6A and 6B are end section views of the woven fibrous electric heating articleof FIG 5, without a raised surface (FIG. 6), with fleece formed on one surface (FIG. 6A), andwith fleece formed upon both surfaces (FIG. 6B).
• FIG 7 is a perspective view of still another embodiment of a woven fibrous electricheating article of the invention in the form of an electric heating pad; and
• FIGS. 8, 8A and 8B are end section views of the woven fibrous heating article of FIG7, without a raised surface (FIG. 8), with fleece formed on one surface (FIG. 8A), and withfleece formed upon both surfaces (FIG. 8B).
• FIG 9 is a somewhat diagrammatic end section view of a preferred embodiment of anelectric conductance heating yarn for a woven fibrous electric heating article of the invention, while FIGS. 10-13 are similar views of alternative embodiments of electric conductanceheating elements for woven fibrous electric heating articles of the invention.
• FIG 14 is a top plan view of an edge region of an alternative embodiment of a wovenfibrous electric heating article of the invention, with a conductive bus attached externally inan edge region; and
• FIG 15 is an end section view of the edge region of a woven fibrous electric heatingarticle of the invention taken at the line 15-15 of FIG 14.
• FIG 16 is a top plan view of an edge region of another alternative embodiment of awoven fibrous electric heating article of the invention, with a conductive bus attachedexternally in an edge region.
• FIGS. 17, 18 and 19 are somewhat diagrammatic representations of otherembodiments of woven fibrous electric heating articles of the invention, including as adaptedto be powered by direct current, e.g., a stadium or camping blanket (FIG. 17) and a garment(FIG. 18), each adapted to be powered from a battery replaceably mounted to the article; andan automobile warming or heating pad (FIG 19), adapted to be powered from an automobilebattery.
• FIGS. 20 and 21 are somewhat diagrammatic perspective views of otherembodiments of electric heating/warming articles of the invention formed of two or morelayers.
• Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
• Referring to FIG. 1, in a first embodiment, a woven fibrous article 10 of theinvention, e.g., an electric blanket or an electric mattress pad, is adapted to generate heatupon application of electrical power. The woven fibrous article consists of awoven body 12formed of aset 14 of non-conductive yarns extending in the warp direction (arrow, W)woven with aset 16 of non-conductive yarns extending in the weft or filling direction (arrow,F). In this first embodiment, theset 14 of non-conductive warp yarns, in a first orcentralregion 18, consists of relatively morecoarse yarns 20 formed of filaments or spun fibersmade of non-conducting insulating material, e.g., such as polyester, acrylic, nylon, cotton,wool, or the like, and theset 16 of non-conductive warp yarns, in one or more second regions, e.g., edge orselvedge regions 22, consists of relativelyfiner yarns 24 formed offilaments or spun fibers. Aconductive bus 26, e.g., a single yarn or multiple yarns in parallel(as shown), to further reduce resistance, extends along the edge orselvedge regions 22. Stillin this first embodiment, theset 16 of non-conductive filling or weft yarns consists ofrelativelyfiner yarns 28 formed of filaments or spun fibers made of non-conductiveinsulating materials, e.g., such as polyester, acrylic, nylon, cotton, wool, or the like, andelectricalconductance heating yarns 30 placed with predetermined spacing. For example, theelectricalconductance heating yarns 30 may be spaced apart symmetrically (e.g., spacing, S₁,FIG. 2) and/or the electricalconductance heating yarns 30 maybe spaced apartasymmetrically, with varying spacing (e.g., spacing, S₂ and S₃, FIG. 3), in order to generatedifferent amounts of heat in different predetermined regions. The electricalconductanceheating yarns 30 may also be made of yarns of relatively different linear resistance spacedapart symmetrically and/or asymmetrically, again to generate different amounts of heat indifferent predetermined regions. The spacing is typically a function, e.g., of the requirementsof heating, energy consumption and heat distribution in the article to be formed. Forexample, the spacing of electricalconductance heating yarns 30 may be in the range of fromabout 0.02 inch to about 2.5 inches. However, other spacing may be employed, depending onthe conditions of intended or expected use, including the resistivity of the conductive yarns.
• According to one preferred embodiment of the invention, the wovenfibrous body 12incorporating the electricconductance heating elements 30 can be completed in an unfleecedstate, e.g., for use as an electric mattress pad 11, as shown in FIG. 4, or the like.
• Alternatively, according to other preferred embodiments of the invention, the wovenfibrous body 12 incorporating the electricconductance heating elements 30 may next besubjected to finishing, e.g., sanding, brushing, napping, etc., to generate a fleece or raisedsurface. For example,fleece 32 may be formed on one surface of the woven body 12 (FIG.4A), orfleece 34, 34' may be formed on both surfaces of the woven body 12' (FIG. 4B). Ineither case, the process of generating fleece on the surface or surfaces of woven body ispreferably performed in a manner to raise the relatively morecoarse yarns 20 in thefirstregion 18, while the relativelyfiner warp yarns 24 with theconductive bus 26 in the secondregions, as well as the relatively finer, tight weft or filling yarns 28 (e.g., high level of twist,high level of tie down), are not raised. The finishing process is also conducted in a manner to avoid damage to the electricalconductance heating yarns 30, like those made with stainlesssteel filaments, that are part of the construction of the wovenbody 12 in the weft or fillingdirection (arrow, F). In particular, fleece 32 (orfleece 34,34') is formed in a manner thatavoids damage to the conductive filaments of the electricalconductance heating yarns 30 thatwould result in an increase in resistance to the point of creating an undesirable local hot spot,or would sever electricalconductance heating yarns 30 completely, which could result inundesirable increased electrical flow elsewhere in the circuit. The material of the wovenbody12 may also be treated, e.g. chemically, to render the material hydrophobic or hydrophilic.
• Referring to FIG. 5, in a second embodiment of a woven fibrous article of theinvention, e.g., anelectrical stadium blanket 40, or other electrical blanket, adapted togenerate heat upon application of electrical power, awoven body 42 is formed of aset 44 ofnon-conductive yarns extending in a warp direction (arrow, W) and aset 46 of non-conductiveyarns extending in a weft or filling direction (arrow, F). In this secondembodiment, theset 44 of non-conductive warp yarns consists of relativelyfiner yarns 48formed of filaments or spun fibers made of non-conductive insulating materials, e.g., such aspolyester, acrylic, nylon, cotton, wool, or the like, and electricalconductance heating yarns50 spaced apart with predetermined spacing. (As described above, the electricalconductanceheating yarns 50 may be spaced apart symmetrically and/or the electricalconductanceheating yarns 50 may be spaced apart asymmetrically, in order to generate different amountsof heat in different predetermined regions, and/or the electricalconductance heating yarns 50may be made of yarns of relatively different linear resistance, spaced apart symmetrically orasymmetrically, again to generate different amounts of heat in different predeterminedregions.) Still in this second embodiment, theset 46 of non-conductive filling or weft yarns,in a first orcentral region 54, consists of relatively more coarse yarns 52 formed of filamentsor spun fibers made of non-conducting insulating materials, e.g., such as polyester, acrylic,nylon, cotton, wool, or the like, and theset 46 of non-conductive filling or weft yarns, in oneor more second regions, e.g., edge orselvedge regions 58, consists of relativelyfiner yarns60 formed of filaments or spun fibers. Conductive yarns orbuses 62, formed, e.g., of oneyarn (as shown) or multiple yarns in parallel, extend along the edge orselvedge regions 58.
• As described above, the wovenfibrous body 42 incorporating the electricconductance heating elements 50 may be completed in the form of an electrical blanket 41 inits unfleeced state (FIG. 6). Alternatively, it may next be subjected to finishing, e.g., sanding,brushing, napping, etc., to generate a fleece.Fleece 64 may also be formed on one surface ofthe woven body 43 (FIG. 6A), orfleece 66, 66' may be formed on both surfaces of thewoven body 43' (FIG. 6B). In either case, the process of generating the fleece on the surfaceor surfaces of woven body is preferably performed in a manner to raise the relatively morecoarse yarns 52 in thefirst region 54, while the relatively finer weft or fillingyarns 60 withtheconductive bus 62 in the second regions, as well as the relatively finer, tight warp yarns48 (e.g., high level of twist, high level of tie down), are not raised. The finishing process isalso conducted in a manner to avoid damage to the electricalconductance heating yarns 50,like those made with stainless steel filaments, that are part of the construction of the wovenbody 42 in the weft or filling direction (arrow, F). In particular, the fleece 64 (orfleece 66,66') is formed in a manner that avoids damage to the conductive filaments of the electricalconductance heating yarns 50.
• Referring to now to FIG 7, in a further embodiment of a woven fibrous article of theinvention, e.g., anelectric heating pad 70, adapted to generate heat upon application ofelectrical power, awoven body 72 is formed of aset 74 of non-conductive yarns extending inthe warp direction (arrow, W) and aset 76 of non-conductive yarns extending in the filling orweft direction (arrow, F). In this embodiment, theset 74 of non-conductive warp yarnsconsists of relativelyfine yarns 78 formed, e.g., of filament 30-500 denier like polyester,nylon, polypropylene, or spun yarn made of 60/1 to 5/1 cotton count like synthetic acrylic,polyester, nylon, or natural fibers like cotton, wool or regenerated fiber like rayon, andelectricalconductance heating yarns 80 spaced apart with predetermined spacing, e.g., asdescribed above with respect to other embodiments of the invention. The electricalconductance heating yarn can be used alone as part of the warp yarn, or plaited with anotherwarp insulator yarn during the weaving. Theset 76 of non-conductive filling or weft yarns, insequential first orcentral regions 82, arrayed in the warp direction (arrow, W), consists ofrelatively morecoarse yarns 84 formed, e.g., of coarse spunyarn 1/1 to 20/1 cotton count orcoarse filament yarn 300 to 5000 denier. The fibers are formed of insulating materials or like, such as synthetic fibers; polyester, nylon, acrylic, polypropylene or natural fibers; cotton,wool, or regenerated fiber like rayon. The fibers may also be a blend. At predetermineddistances along the length of the fabric, insecond regions 86 extending in the weft or fillingdirection (arrow, F) along the borders of thefirst regions 82, theset 76 of non-conductiveweft or filling yarns consists of relativelyfiner yarns 88 formed, e.g., of finer filling yarn,preferred with higher twist and higher tie down (tucking), in filament or spun yarn. At eachsecond region 86,conductive buses 90, formed by insertion of relatively low resistanceelectrically conductive yarns, e.g., group of yarns separated byinsulator yarns 88, to furtherreduce resistance, as weft or filling yarns, extending along the second regions in the weft orfilling direction.
• Once again, as described above, the wovenfibrous body 72 incorporating the electricconductance heating elements 80 maybe completed in the form of an electrical heating pad71 in its unfleeced state (FIG 8). Alternatively, it may next be subjected to finishing, e.g.,sanding, brushing, napping, etc., to generate a fleece.Fleece 92 may also be formed on onesurface of the woven body 73 (FIG 8A), orfleece 94, 94' may be formed on both surfaces ofthe woven body 73' (FIG 8B). In either case, the process of generating the fleece on thesurface or surfaces of woven body is preferably performed in a manner to raise the relativelymore coarse weft or fillingyarns 84 in thefirst regions 82, while the relatively finer weft orfillingyarns 88 with theconductive bus 90 in each of thesecond regions 86, as well as therelatively finer,tight warp yams 78 are not raised. The finishing process is also conducted ina manner to avoid damage to the electricalconductance heating yarns 80, like those madewith stainless steel filaments, that are part of the construction of the wovenbody 72 in thewarp direction (arrow, W).
• Referring to FIG 9, in one preferred embodiment, e.g., as described above withrespect to the electric blanket 10 of FIG 1, theconductive yarn 100 forming the electricalconductance heating elements 30 consists of acore 102 of insulating material, e.g. apolyester yarn, about which extends an electricalconductive element 104, e.g. threefilaments106 of stainless steel wire (e.g. 316L stainless steel) wrapped helically in a sheath about thecore 102, and an outer covering oroverwrap 108 of insulating material, e.g. polyester yams110 (only a few of which are suggested in the drawings) helically wrapped about thecore 102 and thefilaments 106 of the electricalconductive element 30. Theconductive yarn 100is available, e.g., from Bekaert Fibre Technologies, Bekaert Corporation, of Marietta,Georgia, as yarn series VN14.
• The number of conductive filaments in the conductive yarn, and the positioning of theconductive filaments within the conductive yarn, are dependent, e.g., on end userequirements. For example, in alternative configurations, in FIG 10, a conductive yarn 100'has four conductive filaments 106' wrapped as a sheath about a non-conductive core 102'with a non-conductive outer covering or overwrap 108' of polyester yarns 110'. In FIG 11, aconductive yarn 100" has a conductive core of threefilaments 106" wrapped in a non-conductiveouter sheath 108" ofpolyester yarns 110", without an overwrap. Referring toFIGS. 12 and 13, and also referring to FIG 1, in other embodiments,conductive yarns 112,112', respectively, are formed without an outer covering about theconductive filaments 114,114'. Theconductive filaments 114 may be wrapped in a sheath about a non-conductive core116 (FIG. 12), or the conductive filaments 114' may be in the form of a twisted stainless steelwire (FIG. 13). In these embodiments, the non-conductive warpsyarns 20, 24 and the non-conductiveweft or fillingyarns 28 of the wovenbody 12, in particular, the relatively morecoarse yarns, either fleeced or unfleeced, serve to insulate theconductive yarns 112, 112' inthe woven fibrous heating/warming fabric article.
• The resistivity of theconductive yarn 30 can be selected in the range of, e.g., fromabout 0.1 ohm/cm to about 500 ohm/cm, on the basis of end use requirements of the wovenfibrous article. However, conductive yarns performing outside this range can also beemployed, where required or desired. Referring again, by way of example, to FIG 9, thecore102 of the conductive yarn and thesheath material 108 of the outer covering over theconductive filaments 106 may be made of synthetic or natural material. Theouter covering108 may also have the form of a sleeve, e.g. a dip-coated or extruded sleeve. Conductiveyarns of different constructions suitable for use according to this invention can also beobtained from Bekaert Fibre Technologies.
• Referring now to FIGS. 14 and 15, and also with reference to FIG 1, use of relativelyfiner yarns 24, 28 in the edge orselvedge regions 22, in the warp and weft or fillingdirections, respectively, e.g., as compared to thecoarse yarns 20 of thefirst region 18, alternatively permits use ofconductive buses 120 that are appended externally, e.g. along thesurfaces 122 of the edge orselvedge regions 22. It also provides for external securing of theconnection between the electricalconductance heating yarns 30 and the externalconductivebuses 120. For example, after finishing, and after the woven body is heat set for width,conductive buses 120 are provided inopposite edge regions 22 to connect spaced apartelectricalconductance heating yarns 30, in parallel, to a source of electrical power, thereby tocomplete the electrical circuit. Theconductive buses 120 may be formed or attached uponeither surface, or upon both surfaces, of thewoven body 124.
• Alternatively, theconductive bus 120 may instead be applied before, or in theabsence of, finishing (and/or before heat setting), since theconductive buses 120 areadvantageously located in the second edge orselvedge regions 22 of the relativelyfiner yarns24, 28 (which are not finished), and not in a first orcentral region 18 of the relatively morecoarse yarns 20. Any suitable method may be used to complete the circuit. For example, theconductive buses 120 may consist of one conductive yarn, e.g., with a resistivity of, e.g., 0.1to 100 ohm per meter, or of multiple (e.g. two or more) conductive yarns, thus to reduceresistance and to ensure a more positive connection between the electric conductance heatingelements and the conductive buses. Theconductive bus 120 may, at least in part, be appliedin the form of a conductive paste, e.g. such as available commercially from LoctiteCorporation, of Rocky Hill, Connecticut. The conductive paste may be applied as a stripe to asurface of thewoven body 124 in electrical conductive relationship with the electricalconductance heating elements 30, and then connected to the power source. (If necessary, theconductive filaments of the electricalconductance heating elements 30 may be exposed, e.g.,a covering yarn may be removed with solvent or localized heat, e.g. by laser; or the coveringyarn may be manually unraveled, thus to facilitate accessibility to conductive filaments ofeach of the electrical conductance heating yarns.) More preferably, theconductive buses 120,in the form of conductive yarn or thread, are attached upon thesurface 122 of thewovenbody 124, e.g., by stitching, e.g. embroidery stitching, sewing, or with an adhesive, such asby laminating. Alternatively, referring to FIG 16, and again with reference to FIG 1, theconductive bus 130 may consist of localized dots orregions 132 of conductive paste appliedin electrical contact with exposed conductive filaments of the electricconductance heatingyams 30, with aconductive metal wire 134 disposed in electrical conductive contact with, and extending, preferably continuously, between, the localizedconductive paste regions 132.The electricconductive bus 130 may thereafter be covered by a layer offabric material 136joined to overlay a portion or substantially all of the surface of theselvedge regions 122 ofthewoven body 124, e.g., in the form of a cloth trim or edging material attached, e.g., bystitching along the edge of thewoven body 124, or in the form of a second layer of fabricjoined towoven body 124, e.g., by stitching or lamination.
• A conductive bus of the woven fibrous electric heating article of the invention ispreferably flexible, corrosion resistant, with low electrical resistivity, e.g. 0.1 ohm/meter to100 ohm/meter, and mechanically durable. Other considerations include cost, availability inthe market, and ease of fabrication. The conductive bus may thus have the form of a wire,e.g., stranded, twisted, or braided; a conductive-coated textile, e.g., a coated filament orfabric, or a woven ribbon; a foil tape, e.g., adhesive backed, with or without a conductivebacking; a conductive-filled resin, e.g., disposed in a continuous line; or a hybrid textile, e.g.,including tinsel wire or stainless steel filaments, in twisted, braided, stranded, woven orknitted configuration. As mentioned above, the conductive bus may also have the form of asingle yarn, or two or more generally parallel yarns, woven into or stitched upon the fabricbody, or a tape or band of conductive material attached upon the surface of the fabric. In apresently preferred form, the conductive bus may be a narrow woven element, incorporatingsilver-coated copper tinsel wire, either multi-strand or individual strands in parallel, withperiodic floats provided for contact with the conductive yarns, or a narrow woven elementpre-coated with conductive thermoplastic in a stripe pattern, with discontinuous diagonalstripes to provide flexibility and ensure registration with conductive yarns. The conductivebus may also extend in multiple elements extending generally parallel in the edge region ofthe fabric, with similar or different lengths, to connect to distinct sets of electricalconductance heating yarns, in this manner reducing the level of electrical current carried byeach conductive bus in the region close to the source of electrical power. In the case ofconductive buses of different lengths, the resistivity of the individual conductive buses maybe different.
• Theconductive bus 120 is preferably mounted upon the surface of thewoven body124 in a manner to provide strain relief. For example, strain relief attachment may beprovided by sewing theconductive bus 120 to thewoven body 124, by tacking theconductive bus 120 upon the surface of thebody 124 with mechanical fasteners, such assnaps, grommets, staples, or rivets; by over-molding in place strain relief injection-molded"buttons"; or by incorporating strain relief and electrical connection rigid filled resin havinglow viscosity. The electricalconductance heating yarns 30 andconductive bus 120 may beconnected electrically by conductive welding or paste; rivets, snaps, or metal holders orfasteners; interlacing, knitting or weaving in, or combinations of the above.
• The completed circuit is next connected to a power source to supply electrical powerto the electrical conductance heating elements for the required amount of heat generation. Forexample, referring to FIG 1, a woven fibrous article 10 of the invention (an electric blanket)is adapted for connection to a source of alternating current by means ofplug 130 oncord 132for insertion inhousehold outlet 134. Referring to FIGS. 17 and 18, a stadium or campingblanket 140 and agarment 150 of the invention each includes a source of direct current, i.e. abattery pack 142, 152, respectively, e.g., as available from Polaroid Corporation, ofCambridge, Massachusetts, replaceably mounted to the heating/warming fabric article; e.g. inapocket 144, 154, respectively. Referring to FIG 17, the pocket may be secured by a hook-and-looptype fastener 146. Preferably, for certification by Underwriters Laboratories Inc.(UL®), the voltage supplied by the power source to the electrical conductance heatingelements is lower than 25 volts, e.g. a Class II UL® certified transformer may be used to stepdown a 110v power supply to 25 volts or under. Referring next to FIG 19, a warming orheating pad 160 of the invention, e.g. for an automobile seat, is adapted for connection to asource of direct current by means ofplug 162 oncord 164 for insertion into the cigarettelighter orother power outlet 166 of an automobile.
• The resulting product is a woven fibrous electric heating article, e.g., anelectricblanket 90 inches by 90 inches with a 24-volt power supply, with features not available withblankets currently on the market. In a preferred embodiment, the fibrous woven article hasthe characteristics of being: flexible, foldable, portable, able to be washed frequently,comfortable, with zone heating and low voltage (for increased safety).
• A number of embodiments of the invention have been described. Nevertheless, it willbe understood that various modifications may be made without departing from the spirit and scope of the invention. For example, woven fibrous electric heating articles of the inventionmay be formed by any suitable method that results in a woven body formed of non-conductivefibers and conductive elements capable of generating heating when connected toa source of electrical power, and, as desired, or as designed, with non-conductive fibers beingexposed, e.g., in predetermined regions, for finishing at one or both surfaces to create fleece,the finishing being performed in a manner to avoid damage to electrical conductivityperformance of the electrical conductance heating elements joined with the non-conductivefibers in the woven body.
• Referring to FIGS. 20 and 21, woven fibrous electric heating article of the inventionmay also be employed in the form of laminated devices for delivering therapeutic heat to aselected region of the human body. For example, for delivering therapeutic heat upon arelatively large surface region, e.g., of the back or thigh, the heating/warming device 170may be in the form of a wrap or sleeve, with a woven fibrouselectric heating article 172 ofthe invention disposed between opposite fabric layers 174, 176. For delivery ofheating/warming to a more local region, a heating/warming device 180 may be in a formsuitable for mounting to a strap or brace with a woven fibrouselectric heating article 182 ofthe invention laminated with a covering layer of fabric 184.
• Accordingly, other embodiments are within the following claims.

Claims (27)

1. A woven fibrous article adapted to generate heat upon application ofelectrical power, comprising:

   a woven fibrous body comprised of a set of non-conductive warp yarns anda set of non-conductive filling or weft yarns,

   one of said set of non-conductive warp yarns and said set of non-conductivefilling or weft yarns in one or more first regions comprising relatively more coarse yarnsand in one or more second regions comprising relatively more fine yarns with electricalconductor elements extending generally along said second regions of said woven fibrousbody andadapted to connect a plurality of spaced apart electrical conductance heatingelements in a parallel electrical circuit to a source of electrical power, and

   the other of said set of non-conductive warp yarns and said set of non-conductivefilling or weft yarns in the one or more first regions and in the one or more second regionscomprising relatively more fine yarns, with said plurality of spaced apart electricalconductance heating elements in the form of conductive elements joined in said wovenfibrous body with the other of said set of non-conductive warp yarns and said set of non-conductivefilling or weft yarns to extend generally between opposite said second regionsof said woven fibrous body.
2. The woven fibrous article of claim 1, where said woven fibrous articlefurther comprises fleece upon at least one surface of said woven fibrous body, formed byfinishing fibers of the relatively more coarse yarns in said one or more first regions of saidone of said set of non-conductive warp yarns and said set of non-conductive filling or weftyarns in a manner to avoid damage to electrical conductivity performance of the conductiveelements joined with the other of said set of non-conductive warp yarns and said set ofnon-conductive filling or weft yarns of said woven fibrous body.
3. The woven fibrous article of claim 2, wherein said woven fibrous body hasfleece formed in said relatively more coarse non-conductive fibers upon both surfaces.
4. The woven fibrous article of claim 1, wherein, in said one or more firstregions, said set of non-conducting warp yarns comprises said relatively more coarse yarnsand said set of non-conducting filling or weft yarns comprises said relatively more fineyarns.
5. The woven fibrous article of claim 4, wherein said one or more secondregions comprises selvedge or edge regions.
6. The woven fibrous article of claim 1, wherein, in said one or more firstregions, said set of non-conducting filling or weft yarns comprises said relatively morecoarse yarns and said set of non-conducting warp yarns comprises said relatively more fineyarns.
7. The woven fibrous article of claim 6, wherein said one or more secondregions to comprises spaced regions with one or more said first regions disposedtherebetween.
8. The woven fibrous article of claim 6 or claim 7, wherein said one or moresecond regions comprises a plurality of spaced second regions with one or more said firstregions disposed therebetween.
9. The woven fibrous article of any preceding claim, wherein a series of atleast three electrical conductance heating elements of said plurality of electricalconductance heating elements are symmetrically spaced.
10. The woven fibrous article of any preceding claim, wherein selected of saidelectrical conductance heating elements are asymmetrically spaced to provide selectedlocalized regions of heating.
11. The woven fibrous article of any preceding claim, wherein selected of saidelectrical conductance heating elements are asymmetrically spaced to provide selectedlocalized regions of relatively greater heating.
12. The woven fibrous article of any preceding claim, wherein said conductiveelements have the form of a conductive yarn, a conductive wire or a conductive thread.
13. The woven fibrous article of any preceding claim, wherein said fibrous bodycomprises hydrophilic material or wherein said fibrous body comprises hydrophobicmaterial.
14. The woven fibrous article of any preceding claim, wherein said electricalconductor elements are adapted for connecting said plurality of spaced-apart electricalconductance heating elements in the parallel electrical circuit to a power source ofalternating current or to a power source of direct current (eg. a battery, which may bemounted to said woven fibrous body).
15. The woven fibrous article of any preceding claim, wherein said wovenfibrous article further comprises a power source connected to said plurality of spaced apartelectrical conductance heating elements by said electrical conductor elements, said powersource comprising a battery mounted to said woven fibrous body.
16. The woven fibrous article of claim 1, wherein said electrical conductorelements are woven into said second regions of said woven fibrous body (eg. wherein saidelectrical conductor elements are woven into said second regions of said woven fibrousbody with said non-conductive warp yarns, or wherein said electrical conductor elementsare incorporated into said second regions of said woven fibrous body with said non-conductivefilling or weft yarns).
17. The woven fibrous article of claim 16, wherein said electrical conductorelements comprise at least two yarns.
18. The woven fibrous article of any preceding claim, wherein said electricalconductor elements, at least in part, are applied as a conductive paste, or as a conductivehot melt adhesive.
19. The woven fibrous article of any preceding claim, wherein said electricalconductor elements are attached upon a surface in a said second region of said wovenfibrous body.
20. The woven fibrous article of claim 19, wherein said electrical conductorelements are attached by stitching (eg. embroidery stitching), by sewing, by adhesive, bylaminating, by mechanical fastening, or by strain relief fastening.
21. The woven fibrous article of any preceding claim, wherein said electricalconductance heating element has the form of a conductive yarn comprising a core, anelectrical conductance heating filament, and a sheath material wrapped about said core.
22. The woven fibrous article of claim 21, wherein said core comprises saidelectrical conductance heating element and said sheath comprises insulating material; orwherein said core comprises insulating material and said sheath wrapped about said corecomprises said electrical conductance heating element; or wherein said electricalconductance heating element further comprises an overwrap comprising insulating materialwrapped about said core and said sheath.
23. The woven fibrous article of any preceding claim, wherein said electricalconductance heating element has electrical resistivity in the range of about 0.1 ohm/cm toabout 500 ohm/cm.
24. A method of forming a woven fibrous article according to any of claims 1to 23, said method comprising the steps of:

    joining a set of non-conductive warp yarns and a set of non-conductivefilling or weft yarns to form a woven fibrous body, one of the set of non-conductive warpyarns and the set of non-conductive filling or weft yarns in one or more first regionscomprising relatively more coarse yarns and in one or more second regions comprisingrelatively more fine yarns and the other of the set of non-conductive warp yarns and the setof non-conductive filling or weft yarns in the one or more first regions and in the one ormore second regions comprising relatively more fine yarns,

    joining, in the woven fibrous body, with the other of the set of non-conductivewarp yarns and the set of non-conductive filling or weft yarns, the plurality ofspaced apart electrical conductance beating elements in the form of conductive elements,to extend generally between opposite second regions of the woven fibrous body, and

    connecting the plurality of spaced apart electrical conductance heatingelements to electrical conductor elements extending generally along the second regions ofthe woven fibrous body to form a parallel electrical circuit for connection to a source ofelectrical power.
25. The method of claim 24, further comprising the steps of:

    finishing relatively more coarse yarns fibers in the one or more first regionsof the set of the non-conductive warp yarns and the set of non-conductive filling or weftyarns in a manner to avoid damage to electrical conductivity performance of the conductiveelements joined with the other of the set of non-conductive warp yarns and the set of non-conductivefilling or weft yarns of the woven fibrous body.
26. The method of claim 24 or 25 further comprising the step of connecting theconductive element to a source of electric power (eg. a source comprising alternatingcurrent or a source comprising direct current; such as a battery, which may be mounted tothe woven fibrous article) and generating heat.
27. The method of claim 26 further comprising the step of rendering elementsof said woven fibrous body hydrophilic or hydrophobic.

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